/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.mpp.transformation.dag.input;

import org.apache.iotdb.db.mpp.execution.operator.Operator;
import org.apache.iotdb.db.mpp.transformation.api.YieldableState;
import org.apache.iotdb.tsfile.file.metadata.enums.TSDataType;
import org.apache.iotdb.tsfile.read.common.block.TsBlock;
import org.apache.iotdb.tsfile.read.common.block.TsBlock.TsBlockRowIterator;

import java.util.List;

public class TsBlockInputDataSet implements IUDFInputDataSet {

    private final Operator operator;
    private final List<TSDataType> dataTypes;

    private TsBlockRowIterator tsBlockRowIterator;

    public TsBlockInputDataSet(Operator operator, List<TSDataType> dataTypes) {
        this.operator = operator;
        this.dataTypes = dataTypes;
    }

    @Override
    public List<TSDataType> getDataTypes() {
        return dataTypes;
    }

    @Override
    public boolean hasNextRowInObjects() {
        throw new UnsupportedOperationException();
    }

    @Override
    public YieldableState canYieldNextRowInObjects() {
        if (tsBlockRowIterator == null) {
            if (operator.isBlocked() != Operator.NOT_BLOCKED) {
                return YieldableState.NOT_YIELDABLE_WAITING_FOR_DATA;
            }
            if (!operator.hasNextWithTimer()) {
                return YieldableState.NOT_YIELDABLE_NO_MORE_DATA;
            }
            final TsBlock tsBlock = operator.nextWithTimer();
            if (tsBlock == null) {
                return YieldableState.NOT_YIELDABLE_WAITING_FOR_DATA;
            }
            tsBlockRowIterator = tsBlock.getTsBlockRowIterator();
        }

        if (tsBlockRowIterator.hasNext()) {
            return YieldableState.YIELDABLE;
        } else {
            tsBlockRowIterator = null;
            if (operator.isBlocked() != Operator.NOT_BLOCKED) {
                return YieldableState.NOT_YIELDABLE_WAITING_FOR_DATA;
            }
            return operator.hasNextWithTimer()
                    ? YieldableState.NOT_YIELDABLE_WAITING_FOR_DATA
                    : YieldableState.NOT_YIELDABLE_NO_MORE_DATA;
        }
    }

    @Override
    public Object[] nextRowInObjects() {
        return tsBlockRowIterator.next();
    }
}
